Major formatting update to Python library

+ Fixed some spelling mistakes
 + Cleaned up tab/space indentation. Previously some of the samples would not
   work if copied/pasted into a Python interpreter because of mixed tabs/spaces
 + Cleared all trailing whitespace
 + Missing quotation marks in some sample code caused mistakes with printing
   messages
 + Added all import statements to some of the examples that already had some
   import statements

packages/Python/modern_robotics/core.py

@@ -182,7 +182,7 @@ def MatrixLog3(R):
 
 def RpToTrans(R, p):
     """Converts a rotation matrix and a position vector into homogeneous
-    tranformation matrix
+    transformation matrix
 
     :param R: A 3x3 rotation matrix
     :param p: A 3-vector
@@ -305,7 +305,7 @@ def Adjoint(T):
                  np.c_[np.dot(VecToso3(p), R), R]]
 
 def ScrewToAxis(q, s, h):
-    """Takes a parametric description of a scre axis and converts it to a 
+    """Takes a parametric description of a screw axis and converts it to a
     normalized screw axis
 
     :param q: A point lying on the screw axis
@@ -323,10 +323,10 @@ def ScrewToAxis(q, s, h):
     return np.r_[s, np.cross(q, s) + np.dot(h, s)]
 
 def AxisAng6(expc6):
-    """Converts a 6-vector of exponenation coordinates into screw axis-angle
+    """Converts a 6-vector of exponential coordinates into screw axis-angle
     form
 
-    :param expc6: A 6-vector of exponential corrdinates for rigid-body motion
+    :param expc6: A 6-vector of exponential coordinates for rigid-body motion
                   S*theta
     :return S: The corresponding normalized screw axis
     :return theta: The distance traveled along/about S
@@ -1251,6 +1251,8 @@ def InverseDynamicsTrajectory(thetamat, dthetamat, ddthetamat, g, \
              forces/torques at each time step
 
     Example Inputs (3 Link Robot):
+    from __future__ import print_function
+    import numpy as np
     import modern_robotics as mr
     # Create a trajectory to follow using functions from Chapter 9
     thetastart =  np.array([0, 0, 0])
@@ -1267,7 +1269,7 @@ def InverseDynamicsTrajectory(thetamat, dthetamat, ddthetamat, g, \
         dthetamat[i + 1, :] = (thetamat[i + 1, :] - thetamat[i, :]) / dt
         ddthetamat[i + 1, :] \
         = (dthetamat[i + 1, :] - dthetamat[i, :]) / dt
-	#Initialise robot descripstion (Example with 3 links)
+    # Initialize robot description (Example with 3 links)
     g =  np.array([0, 0, -9.8])
     Ftipmat = np.ones((N, 6))
     M01 = np.array([[1, 0, 0,        0],
@@ -1359,6 +1361,8 @@ def ForwardDynamicsTrajectory(thetalist, dthetalist, taumat, g, Ftipmat, \
     ForwardDynamics.
 
     Example Inputs (3 Link Robot):
+    from __future__ import print_function
+    import numpy as np
     import modern_robotics as mr
     thetalist = np.array([0.1, 0.1, 0.1])
     dthetalist = np.array([0.1, 0.2, 0.3])
@@ -1367,7 +1371,7 @@ def ForwardDynamicsTrajectory(thetalist, dthetalist, taumat, g, Ftipmat, \
                    [5.85,  8.17, -2.59], [5.78,  2.79,  -1.7],
                    [4.99,  -5.3, -1.19], [4.08, -9.41,  0.07],
                    [3.56, -10.1,  0.97], [3.49, -9.41,  1.23]])
-	#Initialise robot description (Example with 3 links)
+    # Initialize robot description (Example with 3 links)
     g = np.array([0, 0, -9.8])
     Ftipmat = np.ones((np.array(taumat).shape[0], 6))
     M01 = np.array([[1, 0, 0,        0],
@@ -1413,7 +1417,7 @@ def ForwardDynamicsTrajectory(thetalist, dthetalist, taumat, g, Ftipmat, \
     try:
         import matplotlib.pyplot as plt
     except:
-	    print(The result will not be plotted due to a lack of package matplotlib)
+        print('The result will not be plotted due to a lack of package matplotlib')
     else:
         plt.plot(timestamp, theta1, label = "Theta1")
         plt.plot(timestamp, theta2, label = "Theta2")
@@ -1765,10 +1769,12 @@ def SimulateControl(thetalist, dthetalist, g, Ftipmat, Mlist, Glist, \
     using matplotlib and random libraries.
 
     Example Input:
+    from __future__ import print_function
+    import numpy as np
     from modern_robotics import JointTrajectory
     thetalist = np.array([0.1, 0.1, 0.1])
     dthetalist = np.array([0.1, 0.2, 0.3])
-	#Initialise robot description (Example with 3 links)
+    # Initialize robot description (Example with 3 links)
     g = np.array([0, 0, -9.8])
     M01 = np.array([[1, 0, 0,        0],
                 [0, 1, 0,        0],